Just like cars, airplanes also rely on tires to move on the ground. We rarely hear about cars using rented tires, but it is common practice for airlines to lease tires for their planes. Why is that?
According to aviation news website “Simple Flying,” airlines often lease tires from manufacturers for their planes for several reasons. One important reason is that airplane tires wear out relatively quickly, and leasing allows for quick replacement of tires.
Before understanding why airlines prefer to lease tires instead of purchasing them, we should first understand how airplane tires wear out.
Airplanes use tires to move on the airport, including departing from the boarding gate, taxiing on the runway, and most importantly, taking off and landing. The immense pressure that tires endure depends on the weather conditions and the weight of the aircraft itself and its load.
Compared to flying in the air, the time that airplanes use tires is very short, but it is essential for the aircraft and its mechanical performance, and because the tires are “reused” for every takeoff and landing, they wear out frequently and need to be replaced or refurbished often.
The load on airplane tires can be up to 100 times greater than that of regular car tires. Additionally, airplane tires operate at high speeds during takeoff and landing, making them more likely to wear out.
For example, Air Canada’s Boeing 777 aircraft’s main landing gear has 12 tires, each weighing 120 kilograms, with a diameter of over 1.3 meters.
The average lifespan of main landing gear tires is between 300 and 450 landings, while nose gear tires can typically withstand between 200 and 350 landings. Nose gear tires tend to wear out faster, so their lifespan is shorter.
Depending on the wear and tear, some tires may endure up to 600 landings, while others may need replacement after just 50 landings.
Air Canada noted that all of their aircraft tires are leased from manufacturers such as Goodyear, Michelin, Bridgestone, and they are identified and monitored through serial numbers.
When it comes to maintenance of airplane tires, each tire model has different requirements based on factors such as usage time, number of landings, and degree of wear. Manufacturers use this data to determine which tires need to be refurbished or replaced.
Airlines do not fully own the tires installed on airplanes. The leasing process ensures that tires can be continuously used in the best commercial interest of the manufacturer. Old tires are usually refurbished and can be used up to 7 times before being scrapped.
Unlike car tires, airplane tires have special tread patterns and long grooves that allow them to accelerate and roll faster. These grooves also act as drainage channels, aiding in water runoff.
Due to the heavy weight of airplanes, tires leave black marks on the runway with each landing. These marks accumulate over time and airport maintenance staff must regularly clean them.
In terms of gas filling, airplane tires are filled with nitrogen, which is different from the air filled in car tires. Air contains moisture that can freeze at temperatures as low as -70 degrees Fahrenheit (-57 degrees Celsius), posing a risk for airplanes during high-altitude cruising. Nitrogen only turns into liquid at temperatures as low as -279 degrees Fahrenheit (-173 degrees Celsius).
Another reason for filling airplane tires with nitrogen is the heat generated during landing, and using nitrogen can reduce the risk of combustion. Additionally, nitrogen is inert and does not cause rust on metal, thus extending the overall lifespan of the tires.